1. Field of the Invention
The present invention relates to a releasing agent applying apparatus for preferable use in a fixing apparatus of an image forming apparatus such as a copying machine or a printer and for applying a releasing agent to a fixing roller or the like.
2. Related Background Art
Referring to FIG. 6, there is shown a cross section of a fixing apparatus having an oil applying mechanism.
As shown in FIG. 6, the fixing apparatus comprises a fixing roller 151 which is a rotatably arranged fixing member, a pressing roller 152 which is a pressing member rotating being press-contacted with the fixing roller 151, a releasing agent applying apparatus 153 which is a releasability imparting apparatus, and roller cleaning apparatuses 154 and 155.
There are arranged heaters 156 and 157 such as halogen lamps inside the fixing roller 151 and the pressing roller 152, respectively. In addition, thermistors 158 and 159 are arranged for the fixing roller 151 and the pressing roller 152 so as to be in contact therewith, respectively, thereby regulating temperatures of surfaces of the fixing roller 151 and the pressing roller 152 by controlling voltages to the heaters 156 and 157 via a temperature regulation circuit (not shown).
Additionally, the fixing roller 151 is provided with the cleaning apparatus 154 and the releasing agent applying apparatus 153. The cleaning apparatus 154 cleans offset toner on the fixing roller 151 and the releasing agent applying apparatus 153 applies silicone oil which is a releasing agent to the fixing roller 151, thus facilitating a separation of a transfer paper P which is a recording material from the fixing roller 151 and preventing toner offset.
The cleaning apparatus 154 comprises a cleaning web 154a made of a belt-shaped heat-resistant nonwoven fabric, a pushing roller 154b for pushing the cleaning web 154a against the fixing roller 151, an unwinding roller 154c for unwinding a new cleaning web 154a, and a winding roller 154d for gradually winding up the cleaning web 154a having a deteriorated cleaning performance due to adhering toner. Particularly to prevent a detection failure on the thermistor 158 caused by adhering offset toner on the thermistor 158, the cleaning apparatus 154 is arranged upstream of a rotary direction of the fixing roller 151 relative to the thermistor 158.
Describing a method of winding up the cleaning web 154a, a solenoid (not shown) is turned on and a one-way clutch (not shown) operates when it is determined that copies have been made by a predetermined number of sheets on the basis of a counter (not shown), by which the cleaning web is wound up by a predetermined amount in a reverse direction to the rotary direction of the fixing roller 151. The winding-up in the reverse direction prevents the cleaning web 154a from being wound up in the above rotary direction.
The releasing agent applying apparatus 153 comprises an oil pan 153a which is a storage member for storing a releasing agent such as silicone oil, rollers 153b and 153c which are releasing agent supplying members for scooping up oil which is a releasing agent from the oil pan 153a, an applying roller 153d which is a releasing agent applying member for applying oil from the scooping rollers 153b and 153c to the fixing roller 151, and a regulating blade 153e which is a releasing agent regulating member for regulating an amount of the applied oil from the applying roller 153d. 
Particularly to apply oil uniformly to the fixing roller 151, the releasing agent applying apparatus 153 is arranged downstream of the rotary direction of the fixing roller 151 relative to the thermistor 158. The applying roller 153d is a rotatable roller coated with silicone rubber on its surface made of sponge rubber, abutting the fixing roller 151 for applying the oil. The regulating blade 153e is an elastic blade made of fluororubber or the like for regulating an amount of applied oil by an abutting angle, an abutting pressure, or the like.
In addition, the pressing roller 152 is provided with a cleaning apparatus 155 comprising a cleaning web 155a, a pushing roller 155c, an unwinding roller 155b, a winding roller 155d and the like in the same manner as for the cleaning apparatus 154 for the fixing roller 151, so as to clean toner adhering to the pressing roller 152 via the fixing roller 151.
Furthermore, there is an oil removing blade 160 which is a releasing agent removing elastic member for removing a surplus releasing agent remaining on the pressing roller 152, abutting the pressing roller 152. Without this oil removing blade 160, the surplus releasing agent is stagnant in a nip between the fixing roller 151 and the pressing roller 152, thereby staining a transfer paper or causing an approaching failure to the nip due to a slippage of an OHP transparent laminate film. As materials for the oil removing blade 160, there can be used silicone rubber, fluororubber and the like. The blade abuts the pressing roller 152 by an appropriate approaching amount in a forward or backward direction relative to the rotary direction of the pressing roller 152.
If a transfer paper P is a conveyed in this condition, the fixing roller 151 and the pressing roller 152 rotate, a silicone oil is applied to the fixing roller 151 on its surface as a releasing agent, the transfer paper P is pressed and heated at almost constant pressure and temperature in both directions from the outside of the front and rear surfaces when passing between the fixing roller 151 and the pressing roller 152, by which an unfixed toner image on the surface of the transfer paper P is fluxed and fixed and then a full-color image is formed on the transfer paper P. The image-fixed transfer paper P is separated from the pressing roller 152 by a lower separation claw (not shown) and then ejected to an outside of the apparatus.
In the conventional releasability imparting apparatus such as the above releasing agent applying apparatus 153, however, there is a disadvantage that it may cause the following problem.
In the releasing agent applying apparatus 153, the amount of oil applied to the fixing roller 151 is suppressed by the regulating blade 153e to a predetermined amount. As the number of sheets to be processed increases, the regulating blade 153e is stained by offset toner or paper dust.
Then, if this kind of dust adheres to an edge portion of the regulating blade 153e where the regulating blade 153e abuts the applying roller 153d, only a portion cannot be submitted to the oil amount regulation on the fixing roller 151, thereby causing oil to slip through the regulating blade 153e. 
This causes an oil streak for an OHP or for an image having a large amount of toner, which may lead to quality degradation.
It is an object of the present invention to provide a releasing agent applying apparatus which prevents toner, paper dust or the like from adhering to a releasing agent regulating member.
It is another object of the present invention to provide a releasing agent applying apparatus which enables a releasing agent to be uniformly applied.
It is still another object of the present invention to provide a releasing agent applying apparatus which comprises an applying rotator for applying a releasing agent to an applied member, a supplying member for supplying a releasing agent to the applying rotator, a regulating member for regulating an amount of a releasing agent on the applying rotator, and a cleaning member for cleaning a surface of the applying rotator.
Other objects of the present invention besides those discussed above shall be apparent to those skilled in the art from the description of preferred embodiments of the invention which follows.